The present invention relates to a pedal system for passenger vehicles having a frictional hysteresis mechanism to provide a desired amount of friction when operating a pedal and also to reduce unwanted back pressure on a driver's foot while operating the pedal. More specifically, the present invention relates to a pedal system with a hysteresis mechanism incorporated therein that facilitates assembly and that is robust, yet that maintains a minimum of components and also optimizes the location and operation of the hysteresis mechanism relative to the pedal lever.
Many of the problems and considerations for pedals with hysteresis devices are elegantly set forth in Staker U.S. Pat. No. 6,523,433, and will not be repeated here. However, further improvement is desired at least in the following areas.
Assembly of hysteresis devices can be challenging, since the spring for the hysteresis device must be compressively pre-tensioned during the assembly process. This results in a condition where the assembler needs “three hands” . . . or at least needs the assistance of a fixture or “extra components” to compressively pre-tension the spring and then hold the tension while the components are assembled. It is desirable to provide a simplified system that is more self-contained and more easily assembled, yet that has less requirement for a fixture or for a tooled “aid” to permit efficient assembly.
There are considerable safety and space-related requirements in the under-dash area of driver pedals. The environment is relatively dirty and subject to significant dust, debris, and moisture, especially at the floor level, and this can adversely affect operation of a hysteresis mechanism over time. It is desirable to protect the hysteresis mechanism and position it away from such a dirty environment, to the extent possible. Also, while the device disclosed in Staker U.S. Pat. No. 6,523,433 is relatively compact, it places the hysteresis device within his pedal beam under a pivot axis of the pedal beam. This can cause the pedal beam to become relatively large below the pedal pivot axis, potentially being “too large” for the space allowed in some pedal applications now being designed by vehicle manufacturers in the area adjacent a vehicle floor board and in front of its engine's firewall. For example, a “thick” pedal requires more room from the foot-engaging surface of the pedal to the vehicle floor. A pedal system is desired that allows the pedal beam to remain relatively smaller in cross-sectional size, especially as it extends downwardly and forwardly from the pedal pivot axis.
Additionally, a pedal system is desired that provides a pivot pin location and support that is both robust and also optimally accessible and well-suited for connection to an electrical device for sensing angular position of the pedal beam. In particular, it is desirable to provide balanced support for the pedal pivot pin where the two side walls of a housing that support the pivot pin are integrally formed and interconnected as part of a unitary molding (as opposed to a multi-piece housing). This assures that the opposing ends of the pivot pin are equally well supported, and also eliminates subassembly operations. Equal support at each end of the pedal pivot pin can be very important in the event of a high-force pedal actuation in a crisis situation, such as urgent actuation of the pedal system during a pending vehicle crash, so that one side does not overpower a second side wall in a manner leading to twisting and unbalanced support of the pedal . . . which would in turn lead to other concerns.
Thus, a system is desired having the aforementioned advantages and solving the aforementioned problems.